The invention concerns an optical cable or cable element.
Known in the art is an optical cable consisting of a plurality of individual optical waveguides. The optical waveguides are collected into individual optical waveguide bundles, each optical waveguide bundle being surrounded by a plastic covering. Within the plastic covering, in addition to the optical waveguides, is a compound of incompressible material, e.g. petroleum jelly. Several such optical waveguide bundles are stranded together and the stranded assemblage is surrounded by a plastic jacket. Embedded opposite one another within the wall of the plastic jacket are two tensile-stress-and compression-resistant elements (International Wire and Cable Symposium Proceedings 1999, Page 106).
This known cable is distinguished by a high fibre density. Thus, the cable has up to 144 fibers, with a cable outer diameter of 13.5 mm. The two tensile-stress/compression elements present in the cable jacket give the cable a high load capability in respect of tensile stress and compression. A further advantage is that the fibers are easily accessible.
The object of the present invention is to provide for a cable which has the same advantages as the known cable but which has a smaller outer diameter with the same number of fibers or an equal outer diameter with a higher number of fibers.
This object is achieved by the optical cable or cable element with a plurality of optical waveguide elements which are stranded together and each consist of several optical waveguides, collected into a bundle, and of a plastic covering surrounding the bundle with a maximum free space of 0.1 mm, and of a non-compressible filling compound filling the intermediate spaces between the optical waveguides, and with a layer of longitudinally aligned glass or plastic fibers surrounding the optical waveguide elements and with an extruded outer jacket of a polymer, the outer jacket compressing the layer radially.
The essential advantage of the cable according to the invention compared with the known cable lies in the fact that the tensile-stress/compression elements in the wall of the jacket can be omitted. The bending behaviour of the cable is improved substantially as a result. The tensile-stress/compression stability is provided by the layer compressed by the outer jacket. In addition, the compressed layer protects the optical waveguides from transverse forces, which has a positive effect on the transmission characteristics. By comparison with the known cable, a cable diameter reduction of up to 25% is achieved.